The LWF Blog

Facilities Management & Fire Safety – Water Mist Systems – Part 19

August 3, 2017 2:04 pm

In this fire safety blog series for those who work in facilities management and who have a responsibility for or interest in fire safety, we have recently been discussing water mist systems. Water mist systems were conceived as an alternative to gaseous extinguishing systems. Using only a small amount of water, they have been proven to extinguish very large flammable liquid fires and were originally designed for use on ships.


The potential of the water mist system and its ability to be effective without using a large amount of water has inevitably led to an expansion of the purposes to which it could be used. The application of such systems in residential building applications was inevitable and acknowledged when BRE published their guide in 2006. A working party was put together by the British Standards Institute and finally in 2016, the codes and standards relating to water mist systems were published.


The British Standards relating to water mist systems are now available and are split into industrial and commercial use and domestic and residential use.


BS8458 is the domestic and residential standard


BS8489 is the series for industrial and commercial use


The composition of the fluid used in a water mist system can vary for purpose. In many cases, it is 100% water which is often released at high pressure. Others are known as ‘dual fluid’ and may use water plus air or nitrogen which has the effect of atomising the water at the point of release.


The size of the droplets, speed at which they travel and method of distribution all vary depending upon manufacturer and the suitability for use will depend very much on the purpose to which it will be put, relevant guidance and the overall fire protection measures in place.


A major plus point for some fire safe building projects is that a water mist system can operate from canisters, rather than a water mains, which works well in the short-term. For more sustained use, where access to mains water is not possible, a similar system to that used by non-mains sprinkler systems can be used, whereby tanks are installed with pumps.


The next blog we produce in this series will be Part 20 and will cover Foam Systems. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact Peter Gyere in the first instance on 0208 668 8663.


Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.





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